This invention relates to the communication of pictorial data by a telephony channel having reduced bandwidth such as a paging channel, and, more particularly to the generation of simplified pictures by plural primitive component pictures each of which is characterized by a set of parameters expressible as a sequence of digital bytes.
Various forms of communication channels are in use, the channels varying in their bandwidth in accordance with the data to be transmitted via the channel. For example, in a telephony channel for communication of a paging signal, the allocated bandwidth is significantly smaller than the bandwidth allocated for a telephone channel transmitting normal voice signals. Other communication channels adapted for the concurrent transmission of numerous telephone conversations and/or digital data between computers have still larger bandwidths to accommodate the great amount of data and speed of the data transmission.
It is known that the transmission of pictorial data, such as photographs by way of example, requires the transmission of many data points. Either the data points are to be transmitted slowly over a channel of narrow bandwidth, or the data points can be transmitted rapidly over a channel of larger bandwidth. If one were to transmit normal pictorial data over a channel of substantially reduced bandwidth, such as a paging channel, the pictorial data would take an inordinate amount of time for transmission, such as to render such communication as being impractical in most situations.
It would be useful to be able to communicate pictorial data over a telephony channel of reduced bandwidth, such as a paging channel, because of the considerable convenience offered to parties who need to communicate pictorial data. Small devices for communication at reduced data rates are in use, such as a paging device or Personal Digital Assistant (PDA) or comparable device. One example of such devices is Nokia 9000 Communicator manufactured by Nokia Mobile Phones. Such devices have a display and are small enough to be readily carried about. A portable communication device, such as the PDA, may be capable of one-way or two-way paging, via a communication link such as a GSM (global system for mobile communication) SMS (short message service). By way of example, the PDA may have a large enough display for presentation of a simplified picture and include data input circuitry and circuitry for transmitting information via radio communication. Thus, the PDA may be regarded as being a combination of a portable radiotelephone and a hand-held computer. Facility may be provided for interconnection with both land line telephone networks and cellular telephone networks.
A problem arises in that present communication technology does not enable a user of a portable communication device, such as the PDA, to communicate pictorial data other than the display of possibly a person's name, phone number, and a short message, all of which is presented by way of alphanumeric characters. Diagrams, such as may be used in communicating engineering concepts, or the physical form of an object of interest, cannot be communicated by the common paging channel and presented on the display of a portable communication device.